Selenium and vitamin E supplementation ameliorates the oxidative stress of lactating cows

Abstract

Nutrients with antioxidant function play an important role in immune function and assist in animal health. This work aims to verify the effects of selenium, and vitamin E supplementation and inclusion of sunflower oil in the diet of lactating cows on oxidative stress, immune response and mammary gland health. The trial was carried out with 32 Jersey cows distributed into four treatments: Control concentrate; Antioxidants (concentrate with 3.5 mg organic selenium/ kg in dry matter (DM) + 2000 IU vitamin E/day); Sunflower oil (SFO), concentrate with 4% sunflower oil/kg in DM); and Antioxidants + SFO concentrate, for 76 days. Antioxidants in the diet of cows decreased the total antioxidant activity in the plasma and tended to increase glutathione peroxidase throughout the experiment. Antioxidants tended to increase white blood cells and the addition of SFO tended to increase lymphocytes and basophils in the blood of cows. Antioxidants and oil did not alter the phagocytic function and the reactive oxygen species production from defense cells. The somatic cell score showed tendency to decrease in cows with antioxidant supplementation and to increase with oil supplementation. In milk, mastitis pathogens decreased with antioxidant supplementation and increased with the addition of oil in the diet of cows. The supplementation of lactating cows with antioxidants selenium and vitamin E improved oxidative stress parameters, especially when in combination with sunflower oil in the diet, thus improving the animals' organism against possible harmful effects of free radicals. Antioxidant supplementation also increased the amount of defense cells in the body, increased their phagocytosis activity when stimulated with mastitis pathogens and decreased the amount of pathogens in the mammary gland when supplemented together with the sunflower oil. Cows supplemented with 4% sunflower oil in the diet showed worse mammary gland health due to the increase in mastitis pathogens and increase in somatic cell score in milk.